The present invention relates to a gunsight device for a rotating-wing aircraft, and more particularly a helicopter, comprising a hollow rotor hub, on which there are radially mounted blades constituting said rotating wing, and which is connected to the main transmission box of the aircraft by a drive shaft coaxial with the rotor, said gunsight device comprising a non-rotating gunsight head mounted, by means of a support, at the free upper end of a non-rotating mast arranged coaxially inside said hub and said drive shaft of the rotor, the other end of which mast is fixed into the bottom of the main transmission box, a rolling-contact bearing coaxial with the rotor axis being provided between said hub and said mast.
In such a device, it is important dynamically to match the structure for linking the gunsight head onto the hub, which gunsight head is subjected to vibrations due to it being mounted at the top of a mast securely fastened to a rotor hub likely to be subjected to vibrations, and this is in order to obtain a sufficiently low level of vibrations of the gunsight head allowing correct operation of the optoelectronic members which it contains. Up until now, this problem of dynamically matching the structure for linking the gunsight head onto the hub has not been resolved satisfactorily by the softening or stiffening of the components constituting this linking structure.